Smoked Trout and Pickled Cauliflower Rolls

Ingredients

• 4 long bread rolls (about 19cm long), halved lengthways
• Melted butter, for brushing
• 2 cups torn mixed soft herbs, such as basil, dill and flat-leaf parsley
• ½ thinly sliced Spanish onion
• Extra-virgin olive oil, to taste
• Aïoli, to serve
• 2 whole smoked trout, skin and bones discarded, flesh flaked
• 150 gm Persian feta, crumbled
• Pickled cauliflower
• 1 small cauliflower (about 650 gm), broken into florets
• 1 fennel bulb, thinly sliced
• 3 salad onion bulbs, thinly sliced
• 1 tbsp olive oil
• 1½ tsp yellow mustard seeds
• 500 ml apple cider vinegar (2 cups)
• 140 gm caster sugar
• 1 tbsp sea salt flakes
• 80 gm sultanas
• 1 tsp finely grated ginger
• 4 small green chillies (optional)